Jonathan Freedland compares Theresa May's woes now with those of Arthur Balfour in 1903-06, taking the long view of prime ministers confronted with deep divisions in their own party.

In the early 1900s Prime Minister Arthur Balfour was faced with a seemingly irreconcilable split in his party. Back then, Balfour’s Conservatives were tearing themselves apart over Imperial Preference - a proposal for a free trade zone within the British Empire. Advocates of Imperial Preference saw it as vital to maintaining Britain's place in the world. Opponents saw it as a dangerous folly.

Jonathan Freedland looks at what lessons can be drawn from Balfour's experiences.

Producer: Laurence Grissell